No. 641] THE DUB. 



501 



the essential difference between the human and Droso- 

 phila l.r curves is that, up to what may be desifj:nated as 

 the end of the middle life portion (and even into tlie early 

 part of the old age portion), liuiiiaii briiiu's have a /v7- 

 atively better expectation of life lliaii docs Dmso/iluhL 

 On the other hand, in the extrciiu' old auv portion ot the 

 curve, the DrosopJiiJa ex])eetat ion of lit'c is rclatixely 



better Ihan the linman. The result then is as thouu'h 

 M)nH- o\l<M-nal pouei ha<l M'i/ed tlu' I>>n.n/>lnhi I line at 

 about the mid. 11.' of its e.-ui-e and bent it t.> a sharper 

 ani-I.' in that r.-ion. st ivtchin-' it at that p.)int npwai-d 

 and to the liuhl an.l \n thi^ pi.u-e- e..nx.'it..l it into ih,. 

 human curve. Supp.)se one of the Dr^^sopliil,, I lln.-s, 

 as sliown in K i- :l, to h.' a thin, fiexihh" wln-dch.nu' r..d, 

 po^M-.Mnu ma-. Th.m nn.x.' a point on that r.ul Man.l- 

 inu -,a\ iuM al...N.- th.' final ./ in - /hn^n/>lnla " in Tm. 



life lahh- cni-\v. Th.'n th.' \vh.)l.' of th.' rest .)f the 

 Drosophila curve would fall into al)out the same posi- 



